Microstructures and electrochemical corrosion properties of Mg–Al–Pb and Mg–Al–Pb–Ce anode materials

Abstract

Mg–Al–Pb alloy is a good candidate for the anode material of magnesium seawater battery. For improving the low current utilization efficiency of Mg–Al–Pb alloy, the influence of Ce on the microstructures and electrochemical corrosion properties in a 3.5% NaCl solution was investigated using scanning electron microscope and electrochemical measurements. The results indicate that Ce refines the grain structure of Mg–Al–Pb alloy. The formation of strip Al11Ce3 second phase promotes the uniform distribution of Mg17Al12 phase in Mg–Al–Pb–Ce alloy. The addition of cerium accelerates the discharge activity of Mg–Al–Pb alloy. Due to a large number of cathodic Al11Ce3 and Mg17Al12 phases, Ce promotes the micro-galvanic corrosion and leads to larger corrosion current density and hydrogen evolution rate in Mg–Al–Pb–Ce alloy than those in Mg–Al–Pb alloy. However, Mg–Al–Pb alloy expresses smaller utilization efficiency than Mg–Al–Pb–Ce alloy because of grain detachment.